Slides in this set
How do they form?
When snow falls on an area for a very long time the
bottom layers begin turn into ice due to compression
from the weight of the snow above. The snow and ice
gradually cover the surface land and fill up valleys and
depressions on the surface. The earth becomes
covered by one giant snow field/ice field which creeps
down from the north pole and up from the south pole.
The snow and ice remain for as long as cold
The snow line is the line above which there is
permanent snow, at the poles the snow line is at the
sea. At the equator the snow line is above 6000
The zone of accumulation is the area where snow
and ice builds up over a period of time.
The zone of ablation is the area where snow and ice
recedes due to melting over a period of time.…read more
· Abrasion is when rock fragments carried by a glacier rub against
and like sandpaper, wear away the sides and floor of the valley.
· Freeze-thaw weathering - Glaciers would be less effective at
eroding the landscape without freeze-thaw weathering, it leaves
many frost shattered rocks which are easily removed by the glacier
and then used as tools for abrasion.
· Plucking results from glacial ice melting and then refreezing on to
the solid rock. As the glacier moves away if pulls with it pieces of
U shaped valley
After years of a glacier moving
through a V shaped valley, plucking of
the valley sides and abrasion of the
valley bottom causes it to change
shape into the form of a U shaped
valley also known as a glacial trough.
As seen on the right
The force and erosive power of the ice
is able to wide, deepen and straighten
the valley. The interlocking spurs
become truncated spurs.…read more
· Moraine material moved and deposited by a glacier. There are four main
types of moraine.
· Terminal Moraine: material pushed along at the front end or snout of the
· Lateral Moraine: Material plucked out by or fallen onto the side of the
· Ground Moraine: Material pushed along underneath the glacier.
Contributing to abrasion.
· Medial Moraine: When two glaciers meet their lateral moraines merge into
one medial moraine down the centre of the new longer, wider glacier
· Erratic: huge boulders moved by glaciers and dumped when the ice melts.
· Outwash: Stones and gravels dropped by melt water streams leaving the
glacier snout through little holes.
· Drumlins: mounds moraine left as a glacier retreats, usually made of fertile
boulder clay.…read more